1. Field of the Invention
The present invention relates to an optical ring network, in particular to an optical multi-ring network employing wavelength division multiplexing.
2. Description of the Related Art
It is essential for all optical networks to be configured/scalable to deal with tremendous growth in a data traffic. In this regard, various conventional solutions have been proposed for configuring optical networks and considerable effort has been made to develop various optical transmission systems and optical routing devices to meet this growing data traffic demand.
Optical ring networks based on Wavelength Division Multiplexing (WDM)have several advantages due to their ease of configuration, switching restoration, and reduction of initial costs. Since such WDM optical networks are constructed as an optical ring network which itself is based on WDM, there are future prospects that an optical cross-connect (OXC) may be employed in the optical ring networks to accomplish inter-ring connection between such optical ring networks. As incorporated herein, such an optical network used to connect a plurality of optical single-ring networks is called an optical multi-ring network. In this case, each of the optical single-ring networks includes a plurality of core nodes. However, because an optical multi-ring network is designed to route communication through various channels and because these channels are set in advance, such optical multi-ring networks have a serious drawback regarding their flexibility to coping with data traffic bursts. This results in a significant decrease in total performance of bandwidths.
To overcome these disadvantages, an optical router, based on an optical packet switching (OPS) technique and an optical burst switching (OBS) technique have been used. These optical routers, however, also suffer from drawbacks caused by optical components such as an optical buffer, a high speed optical switch and so forth. For this reason, alternative solutions have been sought, e.g., which make use of a burst delay line, a wavelength converter, etc., all of which are based on optical fibers. However, these alternative solutions have not brought satisfactory results. In addition, these alternative solutions have not proven to be economical.
Accordingly, there is a need in the art for improved optical multi-ring networks.